Temperature controlled safety electric switch



Nov. 30, 1937. J, MCCQRMACK r AL 2,100,665

TEMPERATURE CONTROLLED SAFETY ELECTRIC SWITCH Filed NOV. 16, 1936 2Sheets-Sheet 1 I nveniors Atiornus NOV. 30, J F MCCORMACK ET ALTEMPERATURE CONTROLLED SAFETY ELECTRIC SWITCH Filed Nov. 16, 1956 2Sheets-Sheet 2 j 6/! 1 47/2 h; d 725 /0 1/ A; y M v i M9 94 m i h /4 /06Z1 & 1 0 6 z m Inventors JZ/H-ZZIWzaa/z v J'fijeamrd M By 2mm AttorneysPatented Nov. 30, 1937 PATENT OFFICE TEMPERATURE CONTROLLED SAFETYELECTRIC SWITCH John Francis McCormack, New Haven, and John RichardLeonard,

Gales Ferry, Conn.

Application November 16, 1936, Serial No. 111,100

2 Claims.

This invention relates to what is believed to be a structurally new andnovel electric circuit make and break device such as may be convenientlyclassified in that category of structures having to do with temperatureor heat controlled automatic safety switches, and the purpose of theinvention is to provide a device of this type highly desirable andpracticable for automatically throwing out of operation an oil burner ordomestic air conditioning apparatus in case of fire.

Although I have shown and will describe the complete assemblageincluding the protective housing or casing and wall plate, etc., it isto be pointed out that the chief novelty is predicated upon therelatively fixed and movable contact carrying members and the springactuated plunger means having fusible material incorporated therein in aparticular and preferred manner.

More specifically, the structural novelty resides in the adoption. andcoordination of a pair of spaced parallel. members having a springpressed plunger actuated member mounted therebetween, the parts havingproperly corelated contact elements for electric circuit control, theplunger having manually regulated thrust means associated therewith toclose the switch and having embodied therein fusible means whereby it isautomatically tripped under abnormal heat conditions to break thecircuit for obvious safety reasons.

The chief structural novelty, however, resides in the particularconstruction and use of the plunger which is charged or loaded withfusible material and which is so coordinated with a thrust nut as topermit said plunger, under the action of a spring, to move in adirection to automatically break the circuit when a fire hazard ispresent.

Other features and advantages will become n more readily apparent fromthe following description and accompanying drawings.

In the drawings wherein like numerals are employed to designate likeparts throughout the same:-

Figure 1 is what may be called a top plan view of the novel circuit makeand break device.

Fig, 2 is what may be called a bottom plan view of the relativelymovable contact carrier block.

Fig. 3 is an edge view of the assemblage seen so in Fig. 1.

Fig. 4 is a view partly in section, and partly in elevation, showingcircuit make and break device mounted in an enclosing casing.

Fig. 5 is a top plan view of the relatively stationary contact carrierblock.

Fig. 6 is an enlarged cross sectional view on the line 6--6 of Fig. 4.

Fig. '7 is a detail view of the cap-nut.

Considering now the distinguishable parts of the circuit make and breakdevice, attention first comes to the rectangular block of insulationmaterial shown to advantage in Fig. 5. This is denoted by the numeral 8and is provided with spaced parallel grooves or channels 9, in which therelatively fixed metal contact elements H] are mounted and fastened inplace by suitable fasteners I I. These contact elements H] are notchedas indicated at l2, to accommodate the terminals on the adjacent ends ofthe circuit wires (not shown). The numerals l3 designate binding screwsor posts operable in an obvious manner. The numeral 14 at the center ofthe block designates a stud which is shown in Fig. 4, and is screwthreaded at its outer end as indicated at l5. On opposite sides of thestud are auxiliary assembling and guide forming studs l6. These areformed at their outer ends with screw threaded sockets to accommodatethe assembling screws 11. These assembled screws I! serve to secure themetal bridge plate IS in position. This plate is of any appropriateshape and is located in parallelism with the insulation block 8, beingspaced therefrom, the same having an opening at its center toaccommodate the relatively slidable tubular plunger H3. The plungerforms an integral part of the relatively slidable companion insulationblock 20. This block 20, as shown in Fig. 2, is provided with aperturedextensions 2|, which constitute guides slidable on the guide studs Hi.The block 20 is provided with a plurality of contact pins 22 located forcooperation with the contact element on the block 8. The tubular plungeror sleeve l9 surrounds the central guide stud l4, and has one endsocketed to accommodate a coiled spring 23 in the manner shown in Fig.4. The spring surrounds the guide stud l4 and exerts an outward thruston the sleeve-like plunger is, to urge the contacts 22 and away from thecontacts l0. At the outer end of this plunger sleeve, I provide thefusible filler. This filler is in effect a plurality of plugs 24 fittedinto radial openings in the plunger. It will be observed, however, thatthe sleeve-like portion of the fusible means is in effect a bushing andsurrounds the threaded part of the main stud IS.

The numerals 25 designate a thrust nut which includes a central sleeveportion 26 and a surrounding apertured annulus or rim 21. The numeral 28designates a knurled finger grip. The numeral 29 designates a knurledlock nut. Both of these nuts 29 and 25 are threadedly mounted on thescrew threaded stem E of the main stud IA. The diameter of the rim orshell 21 is such as to permit it to telescope down over the adjacent endportion of the plunger-sleeve 19. The sleeve portion 25 of the thrustnut 25 is in direct thrust contact with the fusible element exposedthrough the adjacent end of the bore of said sleeve. the nut 25'down,this exerts an end thrust pressure on the plunger or sleeve 59 throughthe medium of the contacted portion of the fusible element. By thusturning the nut 25 home, this forces the block 28 toward the block 8againstthe.

tension of the spring 23 and brings the cooperating contact elements 22and Hi together in electrical meeting engagement. When in this positionas shown in Fig. 4, the switch or'circuit make or break device isclosed. This is the normal operating position of parts. Assuming thatthe de- ,vice is built into an airconditioning. apparatus system, or anoil burner system, it would be assembled as shown in Fig. 4. Here, theconductor wire cables'are. denotedby the numerals 30 and are connectedto the ends of5thehousing or casing 35. The plate I3 is mounted in thiscasing, and-isprovided, if desired, by a wall or facing plate 32.Obviously, as before stated, this assemblage in Fig. 4 is .of no moment.The invention is in the assembly depicted to advantage'in Fig. 3.

Assuming that the current is on, and that the circuit make and breakdevice is closed as shown in Figs. 3 and 4, if the roomtemperaturebecomes excessive or abnormal, the fusible element or means24 is melted. Underthe. action of the expansion spring 23,- theplungeri9 isthen released and telescopedinto the cup or rim 2! of the thrustnut25. At the same time, the sleeve portion 25 of the nut rides downinto the bore of thesleeve l9. Consequently, the contactsv I9 and 22separate and the circuit is automatically broken.

structurally speaking, the novelty resides in the relatively stationaryunit made up of parts 8 and is these being joined together through theinstrumentality of the central main stud, l4 and the auxiliary end studs16; in conjunctionwith the relatively movable unit comprising. theinsulation block 213 and the fusible element equipped plunger. That isto say, the disposition of the block 29 between the parts 8 and I8 andthe s1id abie mounting of thesleeve-like plunger 19 on the stud Hi,accompanied by the springs 23 is. an important phase of the invention.Essentially, however, the provision of the fusible element or means 2 1is of outstanding importance, in that this constitutes a fusibleabutment with which the cap-like thrust nut 25 is engaged. Normally,therefore, the nut 25' acts directly against the It is obvious thereforethat by turningplunger and brings the contacts 22 and Ill intoelectrical engagement. -At the same time when the fusible abutmentmelts, the spring then reacts automatically to telescope the plunger I9into the cap-nut 25, bringing about the desired automatic breakage ofthe circuit.

It is thought that persons skilled in the art to which the inventionrelates will be able to obtain a clear understanding of the inventionafter, considering the description in connection with the drawings.Therefore, a more lengthy description is regarded as unnecessary.

Minor changes in shape, size, and rearrangementofdetails coming withinthe field of invention claimed may be resorted to in actual practice, ifdesired.

What we claim as new is:-

1. In a circuit maker and breaker, a plate of conductive material, apair of posts extending therefrom, a block of insulating materialmounted on the free ends of said posts, asecond block of insulatingmaterial slidably mounted on said posts, intermediate the firstmentioned b'lock and said plate for movement towards and from the firstmentioned block,v and tensioned against movement in the formerdirection, complemental contacts on said blocks, respectively, adaptedtobe engaged by movement of the second block to-' ward the first block,a sleeve mounted at one end in the second block to slidably extendthrough said plate, a stud extending from the first block through andbeyond said sleeve, .a sleeve-like nut threaded on to the outer end 'ofsaid stud to telescope into the outer endof said sleeve, and a plug offusable material in the outer endof said sleeve blocking telescopicmovement of said nut into the latter.

2; In a circuit maker and breaker, a plate of conductive material, apair of posts extending therefrom, a block of insulating materialmounted on the free ends of said posts, a second block of insulatingmaterial slidably mounted on said posts, intermediate the firstmentioned block and said plate for movement toward and away from thefirst mentioned block and tensioned against movement in the former.direction, complemental' contacts on said blocks, respectively, adaptedto be engaged by movement of the second block toward the first block, asleeve mounted at one end in the second block to slide ablyextendthrough said plate and having radial slots in the outer end thereof, astud extending from the first block to and beyond said sleeve, and.

' terial extending into said sleeve and blocking telescopic movementofsaid nut intothe latter.

JOHN FRANCIS MCCORMACK. JOHN RICHARD LEONARD.

